In-shoe orthotic heel lifts are commonly recommended for Achilles tendon pathology. It is our understanding that heel lifts may attenuate shock associated with heel strike, and that elevation of the heel decreases load in the Achilles tendon due to shortening of the musculotendinous unit.
Researchers from Munich & Queensland teamed up to investigate whether the addition of a 12mm heel lift to a standard Adidas running shoe (with an intrinsic heel elevation of 10mm) had an influence on loading of the Achilles tendon during walking. Researchers found that the addition of a 12mm heel lift resulted in a significant reduction in ultrasound transmission speed in the Achilles tendon. Essentially, the use of an additional heel lift reduced loading of the Achilles tendon during walking! Small, but statistically significant alterations in vertical ground reaction forces were noted with a heel lift as well.
These findings support the use of orthotic heel lifts as a means of lowering tension within the Achilles tendon during walking activities. Although these findings seem promising, it must be noted that the researchers only compared the heel lift insert to one shoe model. It must also be noted that only male subjects participated in the study, and that these findings were during walking activities, not running. Regardless, a heel lift may be useful, especially early in a progressive-loading intervention program.
Wulf, M., Wearing, S. C., Hooper, S. L., Bartold, S., Reed, L., & Brauner, T. (n.d.). The Effect of an In-shoe Orthotic Heel Lift on Loading of the Achilles Tendon During Shod Walking. J Orthop Sports Phys Ther Journal of Orthopaedic & Sports Physical Therapy, 46(2), 79-86.
Paul Nasri, DPT